The labor market in the United States has gone through a number of noticeable changes, one of which is a rise participation of women in the labor force. A number of studies have investigated the consequences of these changes on wage, income, or earnings inequality in a static framework. This study investigated the consequences of these changes on earnings inequality over time. The earnings inequality among male- and female-headed households is compared. The factors are considered that might have influenced the earnings inequality among female-headed households. Short-term and long-term inequality was measured from 1978-1986. It was found that short-term inequalities generally have a rising trend and contain transitory components; long-term inequalities declined in the early years because of a smoothing of transitory components; and within-group inequalities are the principle determinant of overall inequality. Education, race, age, and marital status were considered as possible contributors to the overall inequality. Education and race were shown to be the most influential factor explaining inequality among female-headed households and explained a third of the observed inequality. Earnings stability profiles reveal the existence of permanent and chronic inequality.